Living aboard? Where to start?
Good for you!!!
My wife & I lived did exactly that from ''92 - 2000 - that is lived aboard/cruised Bahamas in winter, Florida in summer.
Our C&C29, "Southbound" was a premium boat, fitted out with everything - and sold (March 2001) for <$25K.
We were very happy aboard, though you must learn to do without "things", which take space to store, and money to purchase.
Life, afloat, can be cheap ... how cheap is up to you and your boat (maintenance & repair); but $500/month in Bahamas is very doable. Much more in Florida, due to dockage.
Best of luck!!!